The development of Southwest Virginia’s coal mining region is limited by a lack of building sites. Much of the land in this region consists of steep slopes with shallow soils that are poorly suited to residential development. In recent years, widespread surface coal mining has created landforms that are favorably located and configured to support residential housing. However, because such sites are commonly located beyond the extent of public sewers, developing them requires a means for on-site wastewater treatment and dispersal. This publication is written for homeowners, homebuilders, land developers, public officials, and others who may have an interest in building residential housing or other types of development on mined lands that are not accessible to public sewers.

The purpose of this document is to provide guidance on measuring water movement through in situ saturated soil (saturated hydraulic conductivity, or Ksat) as it relates to dispersal and treatment of on-site sewage (wastewater) through an on-site wastewater dispersal area

Soils are composed of solid mineral particles, organic matter, humus, living roots and organisms, and spaces holding air and water (pores). Soil is one of Virginia’s basic natural resources. We are dependent upon the soil as a primary resource of supporting food, fuel, and fiber production. Soils supply nutrients (elements or compounds) necessary for vigorous plant growth for plant growth. Soil moisture affects air pollution and vegetation cover that prevents erosion. Soils are necessary as a base for buildings and roads. Most new houses rely on onsite septic system drain fields to dispose of and treat septic waste through the soil nearby. Soils store carbon and water, clean the water of pollutants and excess nutrients, provide a rooting zone and structural support for plants, and offer habitat to microbes and animals.